The authenticity of olive oil, along with the quality, are the target of many studies and experiments reflecting the high economic value, not only for the consumers all over the world, also for the producers.
The scientific work done for the olive oil, is the result of legislation that relates to accurate characterization and the classification of this product. The goal of these studies is to control changes in olive oil composition for the protection of the consumers from adulteration and producers from unfair competition.
Sometimes unscrupulous producers are blending the olive oil with other cheaper vegetable or seed oils, or refine it with chemical process.
To investigate the constituents of the olive oil, such as triacylglycerols, fatty acids, waxes and sterols, analytical techniques are used. That way the presence or absence of adulterants can be found and the origin of the olive oil can be determined.
Methods used in the analytical methodology are the chromatographic and the spectroscopic.
The chromatographic methods, gas (GC) and liquid (LC) chromatography, are techniques that determine the origin and authenticity of olive oil.
To analyze the fatty acids in olive oils, the methyl esters derivatives are recommended. The composition of fatty acids is different with every harvest and depends on the region, weather conditions, olive ripening and oil bio-synthesis. Studies have proven that fatty acid composition detects adulteration in olive oil.
The gas chromatography (GC) is used for the analysis of sterols. This analysis is used for the detection of olive oil fraud and also to determine the origin and the one mono-variety of olive oil. Alcohols in olive oil are also analyzed with the gas chromatography method which can determine the virgin olive oil. The alcohol components in olive oil include docosanol, tetracosanol, hexacosanol, octacosanol and triter-pine alcohols, which are used to determine the verification of extra virgin olive oil and virgin olive oil, according to Ioannis Boskou.
Volatile components in olive oil can be analyzed with the gas chromatography. The volatile components are used to find out the quality of olive oil.
The liquid chromatography (LG) is used to separate organic chemicals, independent of contamination and volatility.
The main component in olive oil, the trycylglycerols (TAG) have been investigated with liquid chromatography method which determines the mono-varietal origin of olive oil.
The tocopherols are antioxidants in olive oil and the most important component that prevents the olive oil from becoming rancid.
According to Ioannis Boskou, phenols are a lesser component in olive oil and their level depends on factors such cultivation of the olive, maturity, processing and storage.